Figure 3.

Behavioral changes in AR2 mice. A, Rotarod performance presented as latency to fall (at 10 rpm, 180 s at the maximum) began to decline at 5 weeks of age in AR2 mice and rapidly fell to low levels during the initial 5–6 months, remaining stable until 18 months of age. Control mice exhibited full performance (180 s) until ∼12 months of age, followed by slightly lower performance (>164.5 ± 6.4 s) until 24 months. B, Grip strength measured declined with kinetics similar to those of rotarod performance. In A and B, the scores obtained for the AR2 mice (mean ± SEM; n = 28) are indicated as percentage performance of control mice (n = 15). C, AR2 mice exhibited slightly lower body weight than controls (p > 0.05). D, AR2 mice (n = 33) had long lifespans, but the rate of death increased after month 18. The median ± SEM survival was 81.5 ± 16.4 weeks for AR2 mice compared with 105.1 ± 13.5 weeks for control mice (p = 0.0262, log-rank analysis).